Definition:
Hardware Fault Tolerance (HFT) is the ability of a system to continue performing its safety function in the presence of faults.
Key Points:
- Expressed as 0 (no tolerance), 1 (one fault tolerated), etc.
- Drives architecture requirements for higher SIL levels.
Example:
A 1oo2 voting system can tolerate one fault (HFT = 1) without losing safety functionality.
See also: Routes
Cited Source:
- IEC 61508-2:2010, Clause 7.4.4.